A good invoice does more than ask for payment.

Content gives the invoice its job

A proper invoice is the written payment request described by the governing law. Its required information connects an amount to a contractor, the work or contractual payment entitlement, the supply and the payment terms. Contracts can also require supporting information.

Start with the exact statutory list for your jurisdiction. Ontario’s definition appears in section 6.1; Alberta’s in section 32.1; Saskatchewan’s in section 5.1; Manitoba’s in section 85.

Check the details before the delivery

Check who is claiming payment, what was supplied, when it was supplied and how the requested amount was calculated. Add the payment contact and all applicable contractual supporting information.

In Alberta, the invoice must also state that it is intended to be a proper invoice. A generic invoice from another province can miss this requirement.

• Match the invoice to the correct contract and payer.
• Make descriptions and periods specific enough to understand.
• Keep the version actually delivered, with its attachments.
• Preserve delivery and receipt evidence separately.

Missing information does not have one universal effect

Some regimes contain a deeming rule if the recipient does not identify a deficiency within a specified time. Ontario’s current section 6.1 must be read with its deficiency-notification rule. Do not assume that every incomplete invoice stops every clock.

Whether a revised invoice changes an existing date also depends on the governing law and the parties’ agreement. Keep the original and the revision rather than silently overwriting the record.

Use the checklist as a preparation aid

The checklist identifies information you have confirmed. It does not inspect a document or certify compliance, and checking every box is not a legal opinion. If a receipt date or an invoice’s status is contested, get the issue reviewed.